This invention relates generally to valve operating mechanisms for use in internal combustion engines and, more particularly, to an oscillating rocker arm assembly and subassembly having rolling members.
Typically, a rocker arm assembly with rolling members is supported on a support shaft mounted perpendicularly on a support stud extending from the head of the engine. The rocker arm is pivoted on the support shaft, which serves as an inner raceway, by means of drawn cup needle roller bearings mounted on the rocker arm. If desired, a bearing sleeve may be mounted on the support shaft to provide the inner raceway, permitting use of a noncylindrical support arm and facilitating the use of powder metal forming.
In some applications of such rocker arm assemblies, there is a desire to limit axial play between the support shaft and the rocker arm as much as possible. Excess axial play may allow the support structure to contact the rocker arm, preventing the free oscillation provided by the rolling members and causing excess wear. However, because there are manufacturing variations in the components and in the assembly of those components, a zero clearance version of previous rocker arm assemblies has not been practical because of potential cracking of components or other difficulties.
The foregoing illustrates limitations known to exist in present rocker arm bearing assemblies. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.